Recording system



Sept. 25, 1928. 6 1,685,667

G. F. DAVIS RECORDING SYSTEM Filed A ril :5, 1924 Fig.2.

Inventor Guy F. DavLS HLs Attorney Patented Sept. 25, 1928.

UNITED STATES PATENT OFFICE.

GUY I. DLVIS, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

I nnoonnme SYSTEM.

Application filed April 3, 1924. Serial N0. 704,070.

My invention relates to recording systems and apparatus therefor and although not limited thereto, the invention is particularly applicable for recording the operations of circuit controllers, breakers and will be explained as applied for such use. I

In the design of large circuit breakers such as oil switches, it becomes desirable to carefully investigate the operating behavior of the same under load conditions, more particularly, the time of opening. This is rendered diflicult because the switch contacts are generally enclosed and immersed in oil and. the interruption of the circuit is accompanied by dangerous arcs and excessive pressures in the oil switch tank. Also, the operations are generally much too rapid to be followed by the eye. One of the objects of my invention is to provide apparatus to be used in connection with oscillographs or other suitable recording instruments for transferring the mechanical movements of a member such as those of an oil switch, to the recording device so that such movements may be accurately recorded on a record sheet. A further object is to provide in a recording system of this character means for simultaneously making a record, preferably on the same record sheet, of the electrical changes which take place at the switch contact, such as the magnltude of the current flow through the switch and the voltage across the contact during the opening thereof, the various records being so coordinated that the direction, extent and time of movement of the movable switch contacts, together with the magnitude of the current flow and the voltage across the contacts at all positions of the switch are accurately reproduced. From such a record the length and duration of the are formed between the switch contacts, together with the energy dissipated in the arc, may be calculated and the genera]. behavior of the switch studied.

In carrying my invention into effect, I transform the mechanical movements of the switch into electric signalling currents by means of a suitable regulator having a part rigidly fixed to the movable member of the switch. These signalling currents, together with the signalling currents responsiveto the electrical phenomena to be observed are carried to an oscillograph or other current drawing instrument and reproduced 111 the form of properly coordinated graphic records.

for example circuit.-

The features of my'invention which I believe to be novel and patentable will be pointed out in the claims appended hereto. For

a better understanding of my invention, reference is made in the following description to the accompanying drawing, Fig. 1 of which shows the essential details of a preferred embodiment of the mechanical regulator and the layout of a system as arranged for the study of the operation of an oil switch, and Fig. 2 shows a characteristic record produced by the apparatus of Fig. 1. Referring now to Fig. 1, 10 represents an 011 circuit breaker of the enclosed type, the operating characteristics of which it is desired to study. 11 represents an oscillograph by means of which the records are produced. The oscillograph in itselfconstitutes no part of my invention and consequently the details thereof are not shown or described. The oscillograph may be of the type described in United States Patent 919,467, Robinson, or any other suitable type. 12 represents the current regulator for converting the mechanical movements of the circuit breaker 10 into electric signalling currents.

The stationary part of the regulator is mounted on a suitable base 13 which is rigidly mounted above and in fixed relation to the stationary parts of the oil switch 10 by means movable operating mechanism 17 which extends outside of the tank, it being understood. that the part 17 .is connected to the movable switch contacts inside the tank and has a movement proportional thereto. The slider 15 is preferably adjustably mounted on the rod 16 and arranged to be secured inany desired adjusted relation as by means of the nuts 18. The slider is arranged to be reciproc ated in accordance with the movements of the rod 16 between a stationary conductor guide bar 19 and rheostat contact segments 20 and to establish electrical contact between the bar 19 and the contact 20 by means of the flexible conductor member 21 carried on the slider. The end sections of the slider which guide the same are made from insulating material. The contact segments 20 are preferably of equal width and evenly spaced and are separated by insulating segments 22. The

' segments may all be strung on a rod 23 forming, withrod 19 and end clamps 24, the framework of the regulator. The conducting segments 20 are insulated from .the rod 23 and from each .other by the insulating segments 22 and the parts are rigidly held in the rela-' tion shown by the end members 24 of the framework and nuts 25 threaded on the ends of the rod. 1

Every fourth segment 20 beginning from the bottom is connected to a binding post 31 by means of a common wire 26. Every fourth conducting segment, beginning with the next to the bottom segment, is connected to a binding post '32 by means of a common Wire 27. Beginning with the third segment from the bottom, every fourth conducting segment is connected to a bindin post 33 by means of a common wire 28. he remaining conducting segments are connected to a binding post 34 by means of a common Wire 29. Conducing rod 19 is connected to a binding post which in turn is connected by wire 35' through a source of supply 36, which may constitute a couple of dry cells, and a regulating resistance 37 to the vibrator coil 38 of the oscillograph. The other side of the vibrator coil is connected by wire 39 to the binding post 31. Between the wire 39 and bind ing post 32 there is connected a resistance 42; between wire 39 and binding post 33, resistances 42 and 43 are inserted; and between wire 39 and binding post 34, resistances 42, 43 and 44 are inserted. It will now be evident that as the slider 15 is progressively moved along by the rod 16, the circuit of the vibrator coil 38 will be made and broken through progressively varying values of resistance as the slider is moved over each similar group of 4 segments so that the oscillograph reflection produced thereby will be different for adjacent points of contact. The purpose of using diflerent rogressively varying Values of resistance or adjacent points of contact is to make the device an indicator of direction of movement as well as extent of movement and the reason for using the same values of resistance at every fourth contact is to keep the record produced by the oscillograph on a definite portion of the record sheet and at the same time make it distinct. The

significance of this arrangement will appear more clearly when the record sheet of Fig. 2

is explained. I have found that with the 'arrangement described satisfactory results "are produced when the resistances 42, 43 and 44 are given the values'of 10, 20 and 60 ohms respectively. It be evident that it is not essential that four resistance steps be used or that the resistances have the valuespecified 1 to produce the desired results.

If it is merely desired to obtain a record of the progressive time period of a switch operak tion, the remaining vibrators of theoiscillograph may be disconnected. However, the more mportaglfg advantage of my invention Lines 45 and 46 represent the main circuit connections of the oil switch. Potential leads 47 are connected across lines 45 and 46 and lead through a calibrating resistance 48 to the vibrator coil 49 of the oscillograph. This vibrator coil will therefore be responsive to the voltage across the contacts of the oil switch. A third vibrator coil 50 is connected by lines 51 to the secondary of a current transformer 52 and is responsive to the current flowing through the oil switch. In certain cases a shunt may be more desirable than a current transformer at 52. A calibrating shunt 53 may be used across the lines 51 if desired. A fourth vibrator coil 54 connected to an alternating current source 55 of known frequency may be used if desired to establish a timing wave on the record. If the circuit in which the oil switch is contained is an alter: nating current circuit of known frequency, the current and voltage waves responsive thereto may serve the purpose of timing the record and in' this case the vibrator coil 54 need not be'used. ,The oscillograph contains a drum 56 for moving a photosensitive film, which drum may be driven at a definite speed by means of a motor 57 when' the recordsare to be taken. A light source for the oscillograph is shown at 58 and mirrors 59 are provided and arranged so as to be vibrated by their respective vibrator coils in a manner to reflect light beams onto the photosensitive film in accordance with the strength and direction of current flow in such coils.

When it is desired to record the operation of the circuit breaker 10, the switch 60 is closed to energize the light source 58 and to 1 start the motor 57. The switch 10 is then operated either manually or automatically in the desired manner according to the wishes of the investigator. The mechanical movement of the switch actuates the slider 15 of the circuit controller 12 and such'movements ment of the switch as produced bythe vibrator 38. Curve B represents the current flow- -61 the record shows the switch to be in the closed position with no current flowing therethrough. At point 62 a heavy current was thrown on the switch by closing the main circuit at another point. At point 63 the switch under investigation starts to open. At point 64: we note that a voltage starts to appear across the switch contacts, which voltage gradually increases to the open circuit value when the are formed at the switch contacts is interrupted at point 65. At point 66 the switch has fully opened and from point 66 to point 67 the switch closes sli htly and at a slower rate than it opened. This is dueto a slight rebound ot the operating mechanism, or to excessive gas pressure in the switch tank acting on the piston area of the switch plunger. From this record it will be evident that the switch under investigation is of a type in which the movable contacts move downward away from the stationary contacts in' the circuit opening operation. The exact length of the are and the current and voltage of the arc can be determined at any point. The record of the mechanical movement not only shows the rate of movement, but also the direction and extent of movement. It will be seen that the record of the mechanical movement is confined to the upper edge of the record sheet. If the resistance included in the circuit of vibrator 38 was progressively reduced from one end of the regulator to the other, we would still be able to distinguish the rate, direction and extent of movement, but the record would not be confined to one side of the record sheet and would run into the other record and become more or less confused therewith.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with the apparatus which I believe to represent the best'embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other arrangements and for different purposes.

What I claim as new and desire to secure by Letters Patent of the United States is 1. Recording apparatus for investigating the operation of electric controllers comprising, in combination with such a controller, a current regulator responsive to the mechanical movement of the controller, an electric circuit controlled by said regulator, an electric circuit responsive to electrical changes efiected by the controller and a recording device responsive to the currents flowing in said circuits for simultaneously producing coordinated graphic records indicative of the direction and extent of the mechanicalmovement and of the electrical changes produced by said current controller.

2. Recording apparatus for investigating the operation of electric controllers comprising; in combination with such a controller, a current regulator responsive to the mechanical movements of said controller, an electric circuit controlled thereby, an electric circuit responsive to voltage changes efiected by said controller, an electric circuit responsive to current changes efiected by said controller and a recording device responsive to the currents flowing in said circuits for simultaneously producing coordinated graphic records of the direction and extent of the mechanical movement of said controller and of the electrical changes efl'ected thereby.

3. In combination, an oil switch having stationary and movable contacts, a current regulator responsive to the mechanical movement of a movable contact of said switch, an electric circuit controlled by said current regulator, an electric circuit responsive to the current flowing through said switch, an electric circuit responsive to the voltage acrpss,

said switch, a record sheet, and means responsive to the magnitude and direction of the current flowing in said circuits for simultaneously producing coordinated on said record sheet graphic records indicative of the direction and extent of the movement of said movable contact, of the voltage across said switch and of the current flowing therethrough.

4. Apparatus for recording the direction and extent of mechanical movements comprising a rheostat type circuit regulator having a plurality of stationary contacts and a movable contact cooperating therewith, said contacts being arranged so that in moving from one contact to another the movable contact opens the circuit controlled thereby, said regulator being arranged to have regularly re-occurring groups of progressively varying resistance steps, the corresponding resistance steps of each group being equal, a signalling circuit controlled by said regulator, a. measuring instrument connected in said circuit, and a movable record sheet upon which said instrument'records, said apparatus producing a record both when the circuit is interrupted by reason of the movable contact passing between two consecutive stationary contacts of the regulator and when the circuit is completed by reason of the movable contact resting upon a stationar contact.

In witness whereof, I have ereunto' set my hand this 18th day of April, 1924:.

GUY F. DAVIS. 

